Impreza Sedan AWD F4-1820cc 1.8L SOHC (1993)
Air Injection Check Valve: Description and Operation
Check Valve
PURPOSE
Prevents damage to the air control solenoid and air suction valve in the case of an intake backfire.
LOCATION
Inline between the intake manifold and air control solenoid.
OPERATION
Positive intake pressure in the vacuum line pushes on the check valve, closing it.